Fin forming machine



June 15, 1954 J. L. GOLDSMI H FIN FORMING MACHINE 2 Sheets-Sheet 1 FiledFeb. 24, 1953 John L. GO/c/Jm/f/I INVENTOR.

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I 1 l 1 l 1 I I I I] J 7; o fiv 1| ll /k II I I ll I :lkf v- V ATTORNEYSJune 15, 1954 J. GOLDSMITH FIN FORMING MACHINE 2 Sheets-Sheet 2 FiledFeb. 24, 1955 INVENTOR 1 um L. eo/dm/m BY Z II m A TTORNEY-S PatentedJune 15, 1 954 FIN FORMING MACHINE John L. Goldsmith, Houston, Tex.,assignor to Hudson Engineering Corporation,

Houston,

Tex., a corporation of Texas Application February 24, 1953, Serial No.338,415

11 Claims. 1

This invention relates to a machine for finn-ing tubes and relates moreparticularly to a machine for forming a cooling fin on the outer oftelescoped tubes.

In the selection of tubes to be used in conducting one fluid in indirectheat exchange relation with another it is often desirable that the tubesbe of a corrosion resistant metal to prolong their useful life. It isalso desirable that the exterior of the tubes be provided with one ormore cooling fins which increase their exposed area and thereby theirability to transfer heat.

Since corrosion resisting tubes are often fabricated of a metal which isnot sufficiently ductile to permit a high thin cooling fin to be raisedtherefrom, it is common practice to telescope a tube of highly ductilematerial over the corrosion resisting tube and then work the outer tubewith a gang of fin forming rolls to raise the desired cooling fin.

During this fin forming operation the outer tube is tightly squeezedabout the inner tube and a mechanical bond is formed between the twotubes. This mechanical bond prevents excessive loss of efficiency intransmitting heat .between the two tubes. Before this bond is effectedthe tubes are free to slide along each other and considerable diificultyhas been experienced in maintaining the tubes in the desired telescopicrelation until a mechanical bond has been effected along a short lengthof the tubes by the action of the fin forming rolls.

One method of holding the telescoped tubes against sliding along eachother until a mechanical bond is formed along a short length of thetubes is to crimp the forward end of the outer tube over the forward endof the inner tube. The telescoped tubes are then introduced between thegang of rolls by applying a force to the rear end of the inner tube.

The relative length of the telescoped tubes is desirably such that theinner tube projects beyond the outer tube at both ends to facilitateinstallation of the finned tubing in spaced apart tube sheets. When thecrimping method is used this projection can be provided at the rear endof the tubes by cutting tubes to a predetermined relative length beforefinning, but the crimped end of the outer tube must be stripped from theforward end of the finished product to .give the desired projection atboth ends.

It is an object of this invention to eliminate the necessity forcrimping the outer tube over the inner tube and stripping the crimpedend of the outer tube from the finned tubing with its resultant waste oftime, labor and material.

Another object of this invention is to provide a machine for forming acooling fin on the outer of telescoped tubes wherein the tubes areposi-- tioned and fed into the .fin forming mechanism in a predeterminedrelative position withou crimping the tubes together.

Another object of this invention is to provide a machine for relativelypositioning and finning telescoped tubes in which the tubes may beselectively positioned in a plurality of relative longitudinalpositions.

Another object of this invention is to provide a machine for relativelypositioning and finning telescoped tubes which is capable of producingfinished products of various lengths.

Other and further objects will appear from the following description, inwhich is set forth by way of example one illustrative embodiment of theinvention.

In the accompanying drawings wherein like reference numerals indicatelike parts:

Fig. 1 is a pictorial view of a machine illustrating one embodiment ofthis invention;

Fig. '2 is a fragmentary end view on an enlarged scale taken along theline 22 of Fig. 1;

Fig. 3 is a view partly in elevation and partly in verticalcross-section with the receiving and aligning means illustrated inalignment with the central axis of the fin forming rolls, only one ofwhich is illustrated, and with the feeder and telesooped tubes shown inthe position they occupy on initial engagement of the tubes by the finforming rolls; and

Fig. 4 is a view similar to Fig. 3 illustrating the position of theparts at a more advanced stage of the fin forming operation.

Referring to the drawings, an elongate cylindrical base member I0 issupported by a frame comprising legs H reinforced by cross members l2and I3.

Rotatably received about the base member l0 and rotatably positionedthereon by guide lugs l4 secured to the member 10 is an elongatecylindrical carrier [5. The inner diameter of carrier I5 and the outerdiameter of member it are such that carrier [.5 fits closely about basemember H] but is free to rotate without binding.

Positioned approximately midway the length of base member I0 is ananti-sag means in the form of a block I! carried by the frame and a discl6 concentrically disposed about carrier l5. Block IT has a groove I '!aformed in its upper face adapted to receive disc l6 and cooperate withguide lugs I 4 to prevent lengthwise movement of carrier [5. Rollers 18(shown in dotted lines) are journaled in block I11 so as to be enga edby in Fig. 1.

disc i6 and provide a rotatable support for carrier 15. This type ofsupport is preferred as it does not interfere with the rotation ofcarrier 15 about member H).

A fin forming mechanism for raising a cooling fin on the exterior of theouter telescoped tube is provided by a gang of fin forming rolls 23,each having a plurality of discs 24 keyed to axle 25 by keys 26. Therolls are circumferentially arranged about a common central axis withaxles 25 slightly crossed with respect to the central axis so that thediscs of the several rolls will track each other in a helical path. Theaxes of the rolls are also inclined toward the central axis so that thediscs take progressively deeper bites in the tube and form a helical finon the tube as it passes through the fin forming mechanism. It will beunderstood that the rolls may be arranged so as to form one or morehelical fins. The rolls are supported in suitable support structure androtated by a power means, both of which are omitted from the drawingsfor the sake of clarity.

A receiving and aligning means for receiving the telescoped tubes andholding them in alignment with the fin forming mechanism is provided byattaching tube receiver 20 to carrier l by straps l9. Receiver 20 isarranged parallel to the carrier and the longitudinal axis of thereceiver and the central axis of the fin forming mechanism are disposedequidistant from the carrier so that the receiver 20 may be rotated withcarrier l5 and brought into register with the central axis of the finforming mechanism. The rotative positions of receiver 20 are illustratedIn the solid line position the receiver is out of register with the finforming mechanism and unfinned telescoped tubes may be inserted in itsopen end. Receiver 20 can then be rotated to its dotted line positionand the tubes moved into the gang of fin forming rolls.

A guide in the form of tubular member 2|, secured to base member bystraps 22, is positioned between the receiving means and the fin formingmechanism with its axis extending coaxially with the central axis of thefin forming mechanism to insure the alignment of the tubes to be finnedwith the fin forming mechanism before the finning operation is begun.

Associated with receiver 25 is a feeder for feeding the telescoped tubesfrom the receiver into the fin forming mechanism. The feeder comprisesan engaging means having parts for engaging and pushing each of thetelescoped tubes simultaneously and means for moving the engaging meanstoward the fin forming mechanism.

The engaging means comprises a sleeve 26 having an abutment 26a adaptedto engage the outer of the telescoped tubes and a plate 21 slidablyreceived in the sleeve and adapted to abut the inner tube 39. Thetelescoped tubes are engaged and moved toward the fin forming rolls bysleeve 26 and plate 21 which are spaced along the central axis of thefin forming mechanism at different distances therefrom when the receiveris in register with the central axis of the fin forming mechanism. Therelative longitudinal position of abutment 26a. and plate 21 willdetermine the relative position of the ends of the tubes and the tubeswill be moved into the fin forming mechanism in this relationship.

The inner of the telescoped tubes desirably projects beyond the outertube at each end to provide a free section of unfinned tubing tofacilitate fastening the tube in a tube sheet or the like. In order thatthe amount of this projection might 4 be varied plate 21 is providedwith an extension 21a and sleeve 26 is adjustably anchored along thisextension by set screw 28 which is threadedly received in sleeve 26 andspacer 29. It will be understood that this adjustment determines therelative position of the forward ends of the telescoped tubes and thatthe relative position of the rear ends of the tubes will be dependentupon the lengths in which the tubing is cut.

During the fin forming operation the outer tube will elongate slightlyand this elongation should be taken into account when cutting thelengths of outer tubing so that both ends of the inner tube will projectbeyond the ends of the outer tube by whatever distance desired.

In some instances the telescoped tubes are not strong enough towithstand the forces exerted by the fin forming mechanism. To preventcollapse of the tubing by the fin forming mechanism there can beprovided, when necessary, a mandrel 33 of slightly smaller diameter thanthe bore of the inner telescoped tube which is adapted'to lie betweenthe finning rolls during the fin forming operation. A mandrel supportrod can pass through extension 21a and have formed on one end a ball 34adapted to fit in socket 33a in mandrel 33, and be secured therein by anut 35. Nut 35 has a seat surface 35 which complements socket 33a andallows relative rotation between the mandrel support rod 32 and mandrel33.

It will be appreciated that in a machine such as illustrated in thedrawings, it is necessary for the mandrel to be retracted from betweenthe fin forming rolls before the tube receiver can be rotated to an outof the way position for loading. As the engaging means is also retractedin much the same manner the two elements may be advantageouslyreciprocated together by fastening the engaging means to mandrel supportrod32 and reciprocating the rod.

During the fin forming operation the inner tubing is tightly squeezedabout mandrel 33 and some means must be provided to limit the travel ofmandrel 33 so that it will remain between the fin forming rolls duringthe finning cycle. Such a means can be provided by securing a stop 41 tomandrel support rod 32 in a position to engage the end 20a. of receiver20 and prevent further travel of mandrel 33. It will be understood thatwhere the inner tube is strong enough to withstand the action of thefinning mechanism without collapsing the mandrel may be omitted.

The engaging means is adjustably anchored along mandrel support rod 32by set screw 48 to accommodate tubes of different lengths. Thisadjustment coupled with the adjustment of the relative longitudinalposition of sleeve 26 and plate 2'? provided by set screw 28 makespossible the production of finned tubing of various lengths with anydesired relative longitudinal positioning of the telescoped tubes.

Rod 32 is threaded at its end remote from the finning apparatus andpasses through an aperture in collar 31. Nuts 38, one on each side ofcollar 31, secure the rod 32 to the collar and provide for limitedadjustments in the length of rod 32. Collar 31 is provided with a sleeve31a which slidably embraces base support ill. This tubular extensionprevents cooking of collar 31 without interfering with its rotative orsliding movement along base support it. If desired, a heavy grease maybe applied to base support H! to facilitate sliding of collar 31therealong.

Suspended from receiver 20 by straps 39 is a pneumatic actuator tube 40.This pneumatic 5 tube comprises a closed cylindrical tube 4| having apiston 42 slidably received therein. Connecting rod ea, which passesthrough one end of tube M, is connected at one end to piston 42 and hasa threaded portion at its other end which passes through an aperture incollar 3?. Nuts 34 secure th connecting rod 43 to collar 3'! and providefor limited adjustment in the eiiective length of the connecting rod.

Pneumatic tube to is provided with conduits 45 and 48 at its respectiveends through which a pressure fluid may be supplied from a suitablesource, not shown, to actuate piston 42.

During the fin forming operation outer tube 3i is tightly squeezed aboutinner tube 30 by disc 26 and this mechanical bond between the telescopedtubing is usually sufficient to maintain the relative longitudinalposition of the telescoped tubes after they have passed throughapproximately one-third of the fin forming discs 24. Thus, it is onlynecessary that sleeve 2'6 and plate 21 maintain the relative position ofthe telescoped tubing during the initial stages of the fin formingoperation and once the mechanical bond is complete, the movement of theengaging means may be arrested by stop l with the engaging means andmandrel in the position shown in Fig. 4:.

In operation a pressure fluid is introduced through conduit 45 movingpiston 42 and collar 3'! to the left as viewed in Fig. 1, carryingsleeve '25 and plate 2? to their fully retracted position. The receiver26 is then loaded with the unfinned telescoped tubes and rotated intoregister with guide 2!. The pressure is removed from conduit 45 and apressure fluid applied to conduit 46 to move the piston and collar tothe right, and bring the sleeve 25 plate 2'? into engagement with thetelescoped tubes and move them into an initial relative position. Oncontinued movement of the piston the telescoped tubes are passed throughguide 2| and introduced between the tube finning rolls 23. The pressureagainst piston 42 is maintained until a mechanical bond between thetelescoped tubes has been induced by action of the finning rolls 23. Atthis point stop 41 will engage receiver 23 to arrest travel of mandrel33 and the engaging means as illustrated in Fig. 4. After the initialbond between the tubes has been completed and stop 47 engaged byreceiver 20; l

the pressure may be removed from conduit 46 as the engaging means has nofurther function in the finning cycle.

When the finned tube has been completely ejected from between the rolls2%, pressure may be reapplied through conduit 45 to withdraw the mandrel33 until it is entirely contained within receiver 29 so that in rotationof the receiver the mandrel will not strike guide 2!. Carrier l5 maythen be rotated to move receiver 20 into an out of the way position forreloading.

From the foregoing it will be seen that this invention is one welladapted to attain all of the ends and objects hereinabove set forth,together with other advantages which are obvious and which are inherentto the apparatus.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of theclaims.

As many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth or shown in the accompanying 6 drawings is to beinterpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

l. A machine for raising a fin on the outer of telescoped tubescomprising, a fin formin mechanism, a tube receiver for receiving andaligning with the fin forming mechanism telescoped tubes the outer ofwhich is to be finned,

means simultaneously enga-geable with each of the telescoped tubes toposition the en-dsof the tubes in predetermined initial relation to eachother and movable to urge the tubes toward the fin forming mechanism,and means for moving said means toward the fin forming mechanism.

2. A machine for raising a fin on the outer of telescoped tubescomprising, a gang of fin forming rolls circumferentiaily arranged abouta central axis, a tube receiver mounted to align telescoped tubes to befinned with said central axis, engaging means for moving telescopedtubes in said tube receiver longitudinally of said axis toward the rollsand having abutments spaced apart along said axis and at differentdistances therefrom for respectively engaging the inner and outertelescoped tubes to position the ends of the tubes in predeterminedinitial relation to each other and means for moving said engaging meanstoward said rolls.

3. A machine for raising a helical fin on the outer of telescoped tubes,comprising, a gang of fin forming rolls oircumferentially arranged abouta common central axis, a tube receiver for aligning telescoped tubestherein with said common central axis, engaging means comprising asleeve and a plate in the sleeve, said sleeve and plate being slidablewith respect to the tube receiver, and adapted to respectively engagethe outer and inner tubes to axially space their ends apart, and meansfor moving said engaging means toward the rolls.

4. A machine for raising a helical fin on the outer of telescoped tubescomprising; a fin forming mechanism; receiving means for receivingtelescoped tubes and positioning them in alignment with the fin formingmechanism; engaging means comprising a sleeve slidable in the receivingmeans and a plate in the sleeve, said sleeve and plate providingabutment surfaces adapted to engage the outer and inner tubesrespectively to position the ends of the tubes in predetermined relationto each other; a mandrel carried by the engaging means adapted toreceive the tubes thereabout; means selectively urging said engagingmeans and mandrel toward said rolls to introduce said tubes and mandreltherebetween; and stop means preventing travel of said engaging meansand mandrel beyond a predetermined position.

5. The machine of claim 4 wherein releasable anchoring means areprovided for selectively varying the relative positions of the sleeve,plate, and mandrel along the axis of the sleeve.

6. A machine for finning the outer of telescoped tubes comprising, a finforming mechanism, a receiving and aligning means for receivingtelescoped tubes and holding them in alignment with the fin formingmechanism, and a feeder for feeding the telescoped tubes from thereceiving means into said fin forming mechanism, said feeder includingparts for engaging and pushing each of the tubes simultaneously towardthe finning mechanism, said parts being spaced from each other by anamount such as will position the ends of said tubes in predetermined reasleeve slidably surrounding the plate, and releasable means foranchoring the sleeve to the plate whereby the plate may be selectivelypositioned along the axis of the sleeve to position the tubes inpredetermined longitudinal relationship while urging them toward thefinning mechanism.

8. A machine for raising a fin on the outer of telescoped tubescomprising, in combination, a

gang of fin forming rolls circumierentially disposed about a centralaxis, a tube receiver, said tube receiver and gang of rolls beingmovable with respect to each other so that said central axis can bebrought into and out of operative alignment with the longitudinal axisof tubes disposed in said tube receiver, engaging means having spacedapart abutments engageable respectively with the inner and outer tubesto position the ends of the tubes in predetermined initial relation toeach other and movable to urge the thus engaged tubes toward said gangof rolls, and means for moving said engaging means toward said gang ofrolls.

9. A machine for raising a helical fin on the outer of telescoped tubescomprising in combina- 1 tion, a base, a gang of fin forming rollscircumferentially disposed about a central axis, a carrier rotatablymounted on the base, a tube receiver attached to the carrier and adaptedto be selectively rotated to align tubes therein with said central axis,engaging means slidable with respect to the receiver and engageable witheach of the tubes to position their ends in predetermined initialrelation to each other and movable to urge the tubes thus engaged towardthe gang of rolls, and means for moving said engaging means toward saidrolls.

10. A machine for raising a helical fin on the outer of telescoped tubescomprising, an elongate base, a gang of fin forming rollscircumferentially disposed about a common central axis, a carrierrotatably mounted on said base, a tube receiver attached to the carrierand rotatable with the carrier to operatively align tubes in said tubereceiver with said central axis, engaging means comprising a sleeve anda plate in the sleeve adapted to engage the outer and inner telescopedtubes respectively to position the ends of the tubes in predeterminedinitial relation to each other, and means urging the engaging meanstoward the rolls to introduce the workpieces therebetween.

11. A machine for raising a helical fin on the outer oi telescoped tubescomprising; an elongate base, a gang of fin forming rollscircumferentially disposed about a common central axis; a carrierrotatably mounted on said base; a tube receiver attached to the carrierand rotatable therewith to operatively align telescoped tubes in saidreceiver with said central axis; engaging means for tubes in saidreceiver comprising a sleeve and a plate in the sleeve, the sleeve andplate being engageable with the ends of outer and inner tubesrespectively; a mandrel carried by the engaging means adapted to receivethe tubes thereabout; means selectively urging said engaging means andmandrel toward said rolls to introduce said tubes and mandreltherebetween; and stop means preventing travel of said engaging meansand mandrel beyond a predetermined position.

No references cited.

